Sliding Mode Control of Electro-Hydraulic Position Servo System Based on Adaptive Reaching Law

Abstract

For the problem of the system state variable taking a long time to reach the sliding mode surface and the chattering frequency being high in the sliding mode surface, a sliding mode control method based on the adaptive reaching law is proposed, the system state variable is introduced based on the subreaching law, and an improved variable-speed reaching law is added with reference to the characteristics of the hyperbolic tangent function. The sliding mode control method is divided into two stages, namely, the initial state to the critical value s = ±1 and the system state variable reaching the equilibrium point of the sliding mode surface, and the total time obtained is less than the sum of these two stages. Secondly, this method is adopted in the electro-hydraulic position servo system, and a sliding mode controller is established. Through an AMESim/Simulink co-simulation, it is compared with the sliding mode controller based on the traditional exponential reaching law. The results show that this method can effectively reduce the jitter of the system, reduce the time for the system to reach the sliding surface, and improve the robustness of the system.

Design of Backstepping Sliding Mode Control for a Polishing Robot Pneumatic System Based on the Extended State Observer

“…In Section 3, the control law was derived by an analytical method. Based on this, some parameters were adjusted by referring to some literature [41,42] and combining with our model. 6 × 10 4 q 3 4 × 10 6 q 4 1 × 10 8…”

Development of an Adaptive Fuzzy Sliding Mode Controller of an Electrohydraulic Actuator Based on a Virtual Prototyping

“…Additionally, the parameters r 0 , r 1 , r 2 , r 3 , r 4 , r 5 , and r 6 refer to the centers of the membership functions of the output variable's linguistic states Z, PS, PM, PB, NS, NM, and NB, respectively. To specify these parameters, we employ the following selections in Equation (29).…”

“…Comparing their fault-tolerant controller with another QFT controller synthesized without considering the leakage fault, the simulation results showed that the fault-tolerant QFT controller could achieve the prescribed specifications even with internal leakage up to 8.6 L/min, thus confirming its effectiveness and reliability. Similarly, Sun, Dong, Wang, and Li [29] proposed dynamic models for the valve-controlled asymmetric hydraulic cylinder, and a simplified mathematical model of the electrohydraulic position servo system was determined by ignoring the nonlinear factors of the servo valve. They designed a novel sliding mode control (SMC) method based on the adaptive reaching law to control the displacement and velocity of the piston.…”

chattering analysis of an electro-hydraulic backstepping velocity controller

“…Then, the first part of the control law is to reach the sliding mode surface and the second part with a discontinuous term is to keep the state variables inside it. For example, Sun et al [10] use an adaptive reaching law in the SMC to quickly track the desired position of a hydraulic cylinder. Asymptotic convergence in the sliding surface is ensured using the sign function as is shown in the work (Zheng and Su [11]).…”